A few days ago
lisa s

Solve by elimination method?

3r – 7s = -50

7r + 3s = 38

Find the solution as an ordered pair.

Top 3 Answers
A few days ago
john s

Favorite Answer

r=2 and s=8

(2,8)

3r-7s= -50

7r+3s= 38

mult. to make your r’s cross out (or you can do with s’s but i choose r’s)

21r-49s= -350

-21r-9s= -114

the r’s cross out and leaves you with

-49s= -350

-9s= -114

combine everything

-58s=-464

so s=8. the plug that into one of the previous equations and you get r=2. so the answer is (2,8).

if you have any more math q’s ask me cuz i’m a major math geek. hope this helps peace dude.

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A few days ago
cgflann
Multiply the top one by 7 and the bottom one by -3 and then add the equations together:

7(3r-7s)=-50———- 21r-49s=-350

-3(7r+3s)=38———- -21r-9s=-114

Adding the two equations together causes the r terms to cancel leaving you with just -58s=-464

The negative signs cancel each other so you can just drop them and make both sides positive

58s=464

s=464/58= 232/29=8

Plug this back into either equation to solve for r

7r-3(8)=38

7r-24=38

7r=38+24

r=(38+24)/7=62/7

your ordered pair is just (62/7, 8)

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A few days ago
historian
Multiply both sides of the top equation by 3 and the bottom equation by 7.

Then you can add the two equations; the s term disappears because you’re subtracting 21s from 21s. Now you can solve for r and substitute that value into one of the two equations to get the value of s. (Check your work by substuting the value in the other equation to make sure you get the same answer.)

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